I’ve got a weird problem with Patricia’s Windows 8.1 machine. It stopped working while I was in Florida, dying without her being able to restart it. When I got back, I turned off the supply, then back on, and then it booted up (though sometimes it took almost forever). But it kept going to sleep without warning, and couldn’t be woken up without recycling the PS switch. I decided it was probably a bad power supply, the original one from the HP that she had bought, but that I’d kept when I upgraded the motherboard a year and a half ago. I went out and bought a whole new case (the HP case was a PITA to work on), and put in an older 580W supply that I’d had from a previous build. It worked for a day or so, but then started to flake out again in a similar manner. Since it was an old supply, I decided to just go out and buy a new one, a 500W for $40 at Fry’s. But it’s still acting up, so it has to be something other than the supply.
What I don’t understand is how it can not even start up the fans when I hit the front-panel switch. I sometimes have to leave it turned off for a while, which indicates a thermal issue, but just what is the signal to the supply from the MB to turn on? Is there any solution to this other than a new MB?